Technical Field of the Invention
The embodiments of the invention relate to wireless communications and, more particularly, to a transfer of higher data rate audio and video signals over Internet Protocol.
Description of Related Art
Various wireless communication systems are known today to provide communication links between devices, whether directly or through a network. Such communication systems range from national and/or international cellular telephone systems, the Internet, point-to-point in-home systems, as well as other systems. Communication systems typically operate in accordance with one or more communication standards or protocols. For instance, wireless communication systems may operate using protocols, such as IEEE 802.11, Bluetooth™, advanced mobile phone services (AMPS), digital AMPS, global system for mobile communications (GSM), code division multiple access (CDMA), local multi-point distribution systems (LMDS), multi-channel-multi-point distribution systems (MMDS), as well as others.
For each wireless communication device to participate in wireless communications, it generally includes a built-in radio transceiver (e.g. receiver and transmitter) or is coupled to an associated radio transceiver (e.g. a station for in-home and/or in-building wireless communication networks, modem, etc.). Typically, the transceiver includes a baseband processing stage and a radio frequency (RF) stage. The baseband processing provides the conversion from data to baseband signals for transmitting and baseband signals to data for receiving, in accordance with a particular wireless communication protocol. The baseband processing stage is coupled to a RF stage (transmitter section and receiver section) that provides the conversion between the baseband signals and RF signals. The RF stage may be a direct conversion transceiver that converts directly between baseband and RF or may include one or more intermediate frequency stage(s).
Furthermore, wireless devices typically operate within certain radio frequency ranges or bands established by one or more communication standards or protocols. The 2.4 GHz Band (as well as the 5 GHz Band) that encompasses current WiFi and Bluetooth™ protocols has limited data throughput. More recently, higher frequencies in the millimeter wave range are being utilized, such as one of the newer 60 GHz standards, to pursue much higher throughput. Using 60 GHz Band technology, high data rate transfers, such as real-time uncompressed/compressed high-definition (HD) audio and video streams, may be transferred wirelessly between two devices. Due to this inherent real-time requirement for the targeting applications, 60 GHz standard explicitly defines a Quality of Service (QoS) requirement for traffic streams to meet high throughput among devices.
The 60 GHz Band may also be referred to as directional or D-Band and utilizes directional communications, instead of omni-directional (O-Band) propagation of signals (such as at 2.4 GHz and 5 GHz Bands) to overcome the severe path loss experienced at these higher frequencies. The 60 GHz Band devices utilize directional antennas in order to direct the transmitted spectrum energy. One of the protocols/standards being developed utilizing the 60 GHz Band is the IEEE 802.11ad standard. These developing standards call forth certain requirements for devices that are to be compliant to the protocols/standards. One enabling technology for directional signal propagation is beamforming, in which 60 GHz Band devices radiate the propagation energy from a directional antenna or an antenna array and for a receiving antenna or array to orient toward the transmitting device. Another feature is the use of service period scheduling between devices communicating in the 60 GHz Band, instead of the contention-based acquiring as currently used at 2.4/5 GHz.
In one development area for 60 GHz, the Wi-Fi Alliance (WFA) is developing interoperability certification requirements for 60 GHz devices to communicate and transfer high definition video between an audio/video (AV) sourcing device and an AV rendering (sinking) device at close range. A sub-category is the development of wireless transmission of AV content to displays.
As display screen size becomes bigger and resolution (e.g. 1080p) denser, the 60 GHz Band provides one solution to wirelessly transmit AV content data from a content source to a display, because more data may be sent at the higher frequency as compared to 2.4/5 GHz transmissions. Accordingly, A WiFi Display Extension (WDE) is being developed to define and allow for wireless display connections to ensure interoperability and targeted performance.
Although 60 GHz transmissions allow for higher data rate transfer than the currently practiced 2.4/5 GHz WiFi wireless transmissions, one shortcoming is the short range and line-of-sight transmission properties at 60 GHz. Thus, a user watching a program or movie content (such as High-Definition (HD) programming) on a HD display, in which the content is being streamed over the air using the 60 GHz Band, may experience interruptions if the content source is blocked from the display or the content source moves out of range of the display. Note that the content source and/or the display may be a handheld device held by the user. In such an event, it would be advantageous to transfer and couple the video stream over another link, such as the legacy WiFi link that operates at 2.4/5 GHz to maintain the communication.
However, higher frequency data transmissions (e.g. 60 GHz data transmissions), as well as protocols and/or standards that are used for such higher frequency data transmissions (e.g. 60 GHz WDE protocols), being developed are currently not fully compatible with video over lower frequency data transmissions (e.g. 2.4/5 GHz using WiFi protocols). A mechanism is needed to allow for seamless transfer from communication at a higher frequency (e.g. 60 GHz) to communication at a lower frequency (e.g. 2.4/5 GHz) and vice versa. Accordingly, there is a need to find a solution to provide for seamless transition of data transmission from one frequency to a second frequency, where the one frequency is higher than the second frequency, with minimal interruption or minimal degradation of AV content that is being rendered on the display.